Data Center Fabrics with Nokia 7220 SR Linux: Concepts and a Live BGP Use Case from London to Tokyo

Insight:

The Nokia 7220 SR Linux is a next-generation data center networking platform purpose-built to provide high-performance, scale, and automation to cloud and service provider data center. The Nokia 7220 SR Linux is based on an open, Linux-powered network operating system called SR Linux. SR Linux provides a modern, modular, and programmable platform on which to build data-center fabrics based on a leaf-spine architecture using EVPN-VXLAN. With high-density support for 100G and 400G Ethernet, model-driven telemetry, and native integration with automation tools like Ansible, gNMI, and OpenConfig, the Nokia 7220 SR Linux enables operators to deploy agile, resilient, and software-defined data center fabrics. Its open nature and deep programmatic capabilities are perfect for large, multi-tenant, and cloud-based networks where operators need real-time visibility, smooth scalability, and integrated operability across the edge and core.

What is SR Linux router?

Nokia describes SR Linux, or Service Router Linux, as a modern, cloud-native Network Operating System designed for data centres and cloud environments. Unlike traditional router operating systems, SR Linux is genuinely based on Linux, which provides it with the flexibility, openness, and programmability needed for automation-driven networks. SR Linux underpins the architecture of Nokia’s Nokia’s 7220 series routers and switches, allowing them to act as leaf, spine, or border nodes in large data centre fabrics. SR Linux’s architecture is diffracted, meaning that various network processes, such as BGP, EVPN, or OSPF, can run in isolation from each other. If one fails, the others will keep working, which increases reliability SR Linux also offers extensive APIs, including gRPC, JSON, and YANG, as well as compatibility with modern automation, and telemetry systems like Ansible, Terraform, and network controllers. In essence, SR Linux is a high-performance product that inherits the decent features of Nokia’s service router series and combines them with the power and flexibility of Linux, allowing operators to create programmable and resilient data center networks.

Let’s understand using one scenario –

Scenario 1 -- "John works at BT Telecom, where the network consists of Nokia 7220 Linux routers deployed in London within one AS, Cisco 9K series routers operating in Nairobi within another AS, and Juniper MX series routers located in Tokyo in a third AS. Explain how these routers can communicate with each other with using step wise CLI.”

Let’s deep and dive CLI wise --

Step-1 Configuration at London ASBR End

London-ASBR #
/system interface ethernet e1/1
    admin-state enable
    ipv4 address 192.168.12.1/30

/network-instance default
    interface ethernet e1/1

/router bgp
    admin-state enable
    autonomous-system 65001
    router-id 1.1.1.1

    group EBGP-TO-CISCO {
        type external
        peer-as 65002
        neighbor 192.168.12.2 {
            peer-as 65002
        }
    }

    # Advertise local network
    afi-safi ipv4-unicast {
        network 10.1.1.0/24
    }

#Enable IS-IS + Segment routing

router isis 1
    admin-state enable
    net 49.0001.0000.0000.0001.00

    segment-routing {
        enabled true
        global-block 16000 23999
        node-sid 101
    }

#Enable SR

interface ethernet e1/1
    isis 1

Step-2 Configuration at Nairobi ASBR End

Nairobi-ASBR #
interface GigabitEthernet0/0/0/0
 description TO-LONDON
 ipv4 address 192.168.12.2 255.255.255.252
 no shutdown

interface GigabitEthernet0/0/0/1
 description TO-TOKYO
 ipv4 address 192.168.23.1 255.255.255.252
 no shutdown
router bgp 65002
 bgp router-id 2.2.2.2
 address-family ipv4 unicast

 ! eBGP with Nokia (London)
 neighbor 192.168.12.1
  remote-as 65001
  address-family ipv4 unicast

 ! eBGP with Juniper (Tokyo)
 neighbor 192.168.23.2
  remote-as 65003
  address-family ipv4 unicast

 ! Advertise local network
 network 10.2.2.0/24
 
 #Enable IS-IS + Segment Routing
 
 router isis CORE
 net 49.0002.0000.0000.0002.00
 is-type level-2-only

 segment-routing mpls
 !

 address-family ipv4 unicast
  segment-routing mpls
 !
 
 #Node SID allocation
 segment-routing
 mpls
  global-block 16000 23999
  node-msd 16
  
  #Configure Node SID =102
  
  router isis CORE
 address-family ipv4 unicast
  prefix-sid index 102
  

Step-3 Configuration at Tokyo ASBR End

Tokyo ASBR#
set interfaces ge-0/0/0 unit 0 family inet address 192.168.23.2/30
set routing-options router-id 3.3.3.3
set protocols bgp group EBGP-TO-CISCO type external
set protocols bgp group EBGP-TO-CISCO local-address 192.168.23.2
set protocols bgp group EBGP-TO-CISCO peer-as 65002
set protocols bgp group EBGP-TO-CISCO neighbor 192.168.23.1

# Advertise Tokyo network
set policy-options policy-statement EXPORT term 1 from route-filter 10.3.3.0/24 exact
set policy-options policy-statement EXPORT term 1 then accept

set protocols bgp export EXPORT

#Enable Segment Routing MPLS

set protocols isis level 2 wide-metrics-only
set protocols isis interface ge-0/0/0.0 point-to-point
set protocols isis segment-routing mpls
set protocols isis prefix-sid index 103 level 2

#Enable MPLS

set protocols mpls interface ge-0/0/0.0
set protocols mpls interface lo0.0

Post Validation commands 

London-ASBR#
show router bgp summary
show router route-table

Nairobi-ASBR#
show bgp summary
show bgp ipv4 unicast
show route

Tokyo-ASBR#
show bgp summary
show route protocol bgp

Conclusion:

The blog describes the ways in which the Nokia 7220 SR Linux – a state-of-the-art, linux-based and programmable datacenter routing platform – delivers high-performance and how it is optimized to run in multi-vendor networks. A use case is presented in which a Nokia 7220 (AS 65001) in London, Cisco 9K (AS 65002) in Nairobi and Juniper MX (AS 65003) in Tokyo are interconnected between them by means of eBGP How these three devices will interconnect via eBGP with the necessary hands on step-by-step CLI configuration for each vendor is also provided along with verification commands to check that routing has been successfully established.